Abstract: Fusion proteins containing B7-H4 polypeptides are disclosed. The B7-H4 fusion proteins can include full-length B7-H4 polypeptides, or can contain a fragment of a full-length B7-H4 polypeptide, including some or all of the extracellular domain of the B7-H4 polypeptide. Methods for using the fusion proteins to downregulate T cell activation and for the treatment of inflammatory and autoimmune diseases and disorders are also disclosed. The B7-H4 fusion proteins are useful for treating inflammation by inhibiting or reducing differentiation, proliferation, activity, and/or cytokine production and/or secretion by ThI, ThI 7, Th22, and/or other cells that secrete, or cause other cells to secrete, inflammatory molecules, including, but not limited to, IL-1?, TNF-?, TGF-beta, IFN-?, IL-17, IL-6, IL-23, IL-22, IL-21, and MMPs; or enhancing IL-IO secretion by Tregs, increasing the differentiation of Tregs, increasing the number of Tregs, or combinations thereof.

Abstract: Methods for modulating immune responses in a subject are provided. A preferred embodiment provides methods and compositions for reducing or inhibiting transplant rejection in a subject, preferably a human subject. Transplant rejection can be inhibited or reduced in a subject by administering an effective amount of B7-H4 polypeptide, fragments or fusions thereof to inhibit or reduce the biological activity of an immune cell or to reduce the amounts of proinflammatory molecules at a site of transplant. Th1, Th17 and Th22 cells are exemplary T cells that can be targeted for inhibition by B7-H4 polypeptides, fusion proteins or fragments thereof to inhibit or reduce inflammation.

Abstract: The present invention relates to antibodies (including anti-B7-H4 antibodies) and their antigen-binding fragments and to other molecules (including fusion proteins that bind to the cognate antigen/receptor, etc.) that are capable of immunospecifically binding to B7-H4 and the uses of such molecules in the diagnosis and the treatment of cancer and other diseases. The invention particularly concerns the use of such molecules to retard or prevent tumor growth, inhibit tumor-mediated suppression, eliminate tumors and/or deplete or block the activity of tumor associated macrophages (“TAMs”) so as to alter their activity and/or decrease TAM—mediated immune suppression.

Abstract: Methods and compositions for treating an infection or disease that results from (1) failure to elicit rapid T cell mediated responses, (2) induction of T cell exhaustion, T cell anergy or both, or (3) failure to activate monocytes, macrophages, dendritic cells and/or other APCs, for example, as required to kill intracellular pathogens. The method and compositions solve the problem of undesired T cell inhibition by binding to and blocking PD-1 to prevent or reduce inhibitory signal transduction, or by binding to ligands of PD-1 such as PD-L1, thereby preventing (in whole or in part) the ligand from binding to PD-1 to deliver an inhibitory signal. The immune response can be modulated by providing antagonists which bind with different affinity (i.e.

Abstract: Methods of treating cancer and infectious diseases utilizing a treatment regimen comprising administering a compound that reduces inhibitory signal transduction in T cells, in combination with a potentiating agent, such as cyclophosphamide, to produce potent T cell mediated responses, are described. Compositions comprising the PD-1 antagonists and potentiating agents useful in the methods of the invention are also disclosed.

Abstract: The present invention relates to antibodies and their antigen-binding fragments and to other molecules that are capable of immunospecifically binding to B7-H1 or PD-1. In some embodiments such molecules are additionally capable of modulating the ability of B7-H1 or B7-DC to bind to PD-1 or are capable of affecting the signaling activity of the B7-H1 or PD-1. The invention additionally concerns the uses of such molecules in the diagnosis and treatment of cancer and other diseases.

Abstract: Methods of treating cancer and infectious diseases utilizing a treatment regimen comprising administering a compound that reduces inhibitory signal transduction in T cells, in combination with a potentiating agent, such as cyclophosphamide, to produce potent T cell mediated responses, are described. Compositions comprising the PD-1 antagonists and potentiating agents useful in the methods of the invention are also disclosed.

Abstract: Methods of treating cancer and infectious diseases utilizing a treatment regimen comprising administering a compound that reduces inhibitory signal transduction in T cells, in combination with a potentiating agent, such as cyclophosphamide, to produce potent T cell mediated responses, are described. Compositions comprising the PD-1 antagonists and potentiating agents useful in the methods of the invention are also disclosed.